Your sub experience: Easy or hard?

Started off with one, added another shortly thereafter with good success and a bit of trial and error.

It is essential that you choose a sub or subs with room correction for best results, if you do not otherwise already have RC elsewhere in your system at present. It is very effective at aiding in the integration process, especially one with an infinitely variable X-over point.

According to my experience the choice of a sub (or more than one) depends also very much on your room and its acoustics - and, of course, on the quality of the components in your stereo system (low, middle, consumer, high end). 

I assume nobody out there knows or remembers the make of the sub I use: Acustik-Lab Stella Novus (originally spelled name), a Swiss made component which was very in demand in Asia in its time (and very costly, unfortunately). It allows settings in many ways, which was prior to today's DSP. (The company no longer exists.) So my favorite crossover setting  is 42 Hz...quite discreet. 

Set-up was quite easy, and I needed just some days to find the right listening setting (for me). As another A'goner wrote, the recordings (LP & CD) vary, and depending on that I am able to adjust the sub's settings (by remote control). 

Just a quick note to everyone.

Thank you very much for sharing your insights and staying (mostly) on topic.

Erik

Trying to integrate one was very difficult. Never blended right and never sounded balanced to me. But integrating two was much easier and sounded great. I settled on line-level with a cable from amp speaker taps to a powered subwoofer for each of the two channels. 

I've run REL s/510 SHO with focal Sopra 2, Harbeth 30.2 and Harbeth SHLs 5 with generally good results in a purpose built room about 13x22. I then changed to a JL 113v2 and the JL crossover, CR-1 and now run this with Wilson Sabrina, crossed over at 60 hz. This set up is the best so far, very seamless integration due to both the JL's auto DSP room tuning and the flexibility of the CR1. I also use GIK room treatment and bass absorbers. The bass is subtle and tuneful, no boom. Roon also provides another means of EQ on the fly btw. I think most times subs get set to be too loud and then can border on being perceived as boomy.